There is a problem for "yum". At first the "yum" can be used. But now it can't work right.when I run command "yum update",there is some errors.
The errors is below:

[root@localhost navy]# yum update
Loading "installonlyn" plugin
Setting up Update Process
Setting up repositories
macromedia [1/6]
macromedia 100% |=========================| 951 B 00:00
livna [2/6]
livna 100% |=========================| 951 B 00:00
core [3/6]
Cannot find a valid baseurl for repo: core
Error: Cannot find a valid baseurl for repo: core

I hope someone can hlpe me.

thanks!

They were updating that site, it should be working now/soon.

Thanks!
Now it is OK!